From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752744AbZIICxG (ORCPT ); Tue, 8 Sep 2009 22:53:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752169AbZIICxF (ORCPT ); Tue, 8 Sep 2009 22:53:05 -0400 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.124]:51245 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751922AbZIICxF (ORCPT ); Tue, 8 Sep 2009 22:53:05 -0400 Subject: Re: [PATCH 1/2] tracing: Add sysctl to enable/disable tracing on oops From: Steven Rostedt Reply-To: rostedt@goodmis.org To: Li Zefan Cc: KOSAKI Motohiro , Ingo Molnar , Frederic Weisbecker , LKML In-Reply-To: <4AA715A3.8040108@cn.fujitsu.com> References: <4AA7092C.4070706@cn.fujitsu.com> <1252461867.11070.6.camel@gandalf.stny.rr.com> <20090909113231.0CE6.A69D9226@jp.fujitsu.com> <4AA715A3.8040108@cn.fujitsu.com> Content-Type: text/plain Organization: Kihon Technologies Inc. Date: Tue, 08 Sep 2009 22:53:04 -0400 Message-Id: <1252464784.12982.4.camel@gandalf.stny.rr.com> Mime-Version: 1.0 X-Mailer: Evolution 2.26.3 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 2009-09-09 at 10:40 +0800, Li Zefan wrote: > > I have another silly question. > > Why should we call tracing_off() in oops_enter()? > > > > I guess it's because trace outputs generated during oops can > overwrite/mess up those generated before oops? > > It was added by this commit, but I can't find trace_printk_on_oops. That's because Thomas did not bother looking up the actual variable he was talking about. s/trace_printk_on_oops/ftrace_dump_on_oops/ -- Steve > > commit bdff78707f3ce47e891f3201c9666122a70556ce > Author: Thomas Gleixner > Date: Fri Jul 24 15:30:45 2009 -0400 > > trace: stop tracer in oops_enter() > > If trace_printk_on_oops is set we lose interesting trace information > when the tracer is enabled across oops handling and printing. We want > the trace which might give us information _WHY_ we oopsed. >